JP5430392B2 - Constant differential pressure fuel flow controller - Google Patents

Description

  The present invention relates to a constant differential pressure type fuel flow control device that continuously adjusts the heating power of an oil burning burner used in an oil burning water heater or the like from maximum to minimum.

A constant differential pressure system is adopted as a fuel flow control device for a burner for an oil combustor. As an example of this, Patent Document 1 can be cited. In the Patent Document 1, the fuel supply passage 3 toward the fuel injection nozzle 15, for example a Teisa圧pump constant pressure supply of 7 kgf / cm ^2, for example, 1 kgf / cm ² or et adjustable output 5 kgf / cm ² The two electromagnetic pumps of the control pump 9 are connected in series, and a return flow path 21 communicating with the return hole of the fuel injection nozzle 15 is connected between the constant pressure pump 13 and the control pump 9. Therefore, the sprayed fuel is controlled steplessly from the fuel injection nozzle 15 by inputting a voltage pulse obtained by phase-controlling the commercial power supply to the control pump 9 and making the discharge capacity variable.

Japanese Patent No. 3291622

  In such a gun type oil burner such as an oil water heater used in a constant differential pressure type fuel flow control device, it is controlled from maximum combustion to minimum combustion during use, and at which point the operation is stopped (extinguishing) But it happens and is not fixed. On the other hand, the ignition is performed with the minimum combustion or an injection amount in the vicinity thereof in order to reduce the smoke and ignition sound at the time of ignition.

However, as described above, fire extinguishing is performed at an unspecified time between the maximum combustion and the minimum combustion. Therefore, at the time of fire extinguishing, the driving of the constant pressure pump 13 is stopped, and the fuel supply pressure at the time of fire extinguishing is inside. Remains. Particularly supply pressure is higher with ^{10kgf / cm 2 ~13kgf / cm 2} , the pressure continues a state in which accumulated inside by the action of the pressure regulating valve or solenoid valve.

  On the other hand, a gun-type oil burner is basically a high-load burner, and has a large rate of change of enthalpy (Δh / dt) in the combustion chamber at the time of ignition, and therefore remains in the constant differential pressure pump 13. Since the fuel pressure to be applied is instantaneously applied at the time of ignition and exceeds a predetermined ignition pressure, problems such as smoke generation and increased ignition noise have occurred as a transient phenomenon at the time of ignition.

  On the other hand, recent oil water heaters have many instantaneous direct water pressure systems, and the amount of hot water stored in the heat exchanger is extremely small.For example, after a fire extinguishing signal is sent to the control pump, the fire extinguishing is made after shifting to minimum combustion. There is no time to squeeze it. If such an operation is performed, the heat exchanger will be damaged by the thermal power.

  The present invention aims to reduce the supply pressure remaining in the constant differential pressure pump to a predetermined pressure during re-ignition when the operation is stopped (when the fire is extinguished). The purpose is to eliminate.

A constant differential pressure type fuel flow control device according to the present invention includes a control pump that sucks fuel from a fuel tank and supplies a fuel supply passage to a fuel injection nozzle, the output of which is variable, and adds a constant output to the output of the control pump. with placing the Teisa圧pump output, constant difference pressure fuel return passage connected to the return hole of the fuel injection nozzle is connected to the fuel supply passage between the Teisa圧pump and the control pump In the flow rate control device, a pressure regulating valve is provided on the discharge side of the constant differential pressure pump, and a relief passage is provided in parallel with the pressure regulating valve and the constant differential pressure pump, and a check valve is provided in the relief passage. A constant differential pressure type fuel flow control device, characterized in that an orifice connected in series to the check valve is provided, and the check valve is provided in a pressure receiving piston constituting the pressure regulating valve.

  As a result, when the operation is stopped during combustion, the supply pressure remaining on the discharge side of the constant differential pressure pump opens the check valve and is discharged to the suction side of the constant differential pressure pump through the relief passage. The residual pressure on the discharge side drops. Then, the check valve is opened until reaching the cracking pressure. By appropriately setting the cracking pressure, the check valve is kept closed during operation, that is, when the constant differential pressure pump and the control pump are operated.

In addition, an orifice is provided in series with the check valve on the relief passage , thereby smoothing the pressure fluctuation and preventing the check valve from jumping.

Further, the check valve is provided to the pressure receiving piston constituting the pressure regulating valve, thereby, it can be integrated with the pressure regulating valve. Further, the check valve is specifically a valve seat fixed to the pressure receiving piston constituting the pressure regulating valve and having a through hole in the center thereof, a valve body seated on the valve seat, and the valve body that presses the valve body. It lies in comprising more the spring in the spring case of sticking to the valve seat (claim 2).

Since the orifice is fixed to the pressure receiving piston and is provided in a through hole formed in the valve seat (Claim 3 ), a special passage is not formed, and the through hole formed in the center of the valve seat is processed. Can be formed simultaneously.

According to claim 1 of the present invention, when the pressure on the discharge side of the constant differential pressure pump reaches or exceeds the cracking pressure of the check valve when the operation of the combustor is stopped, the check valve is opened and the constant differential pressure is released from the relief passage. The pressure is returned to the suction side of the pump, and the pressure on the discharge side of the constant pressure pump decreases. Thereby, at the time of re-operation, an ignition pressure does not increase, it becomes a predetermined ignition pressure, smoke generation can be prevented, and an ignition sound can be reduced. Note that during operation of the combustor, remains closed without reaching the cracking pressure of the check valve Waso not a loss of supply pressure.

Further, according to the invention of the same paragraph , by adding the orifice, the pressure is smoothed and the check valve is prevented from jumping. Further, since the check valve is provided on the pressure receiving piston constituting the pressure adjusting valve, it has an advantage that it can be integrated.

According to the invention of claim 3 , since the orifice is provided in the through hole formed in the valve seat fixed to the pressure receiving piston, the through hole formed in the center of the valve seat without forming a special passage. It has the advantage that it can be formed at the same time.

It is a schematic block diagram of the constant differential pressure type fuel flow control device in which this invention is used. It is a longitudinal cross-sectional view of a fuel flow control apparatus. It is a cross-sectional view of a fuel flow rate control device provided with a check valve, an orifice, and a pressure regulating valve as an internal pressure relief mechanism.

  Embodiments of the present invention will be described below with reference to the drawings.

  In FIG. 1, a schematic diagram of an embodiment of the present invention is shown. From an oil tank 1, fuel (petroleum) is supplied to a fuel flow control device 3 through a fuel supply passage 2 and finally from an injection nozzle 4. Be injected.

  The fuel flow control device 3 is divided into units, and is roughly composed of a control pump block 6 having a control pump 8 and a constant differential pressure pump block 7 having a constant differential pressure pump 9.

Control the pump 8 of the control pump block 6, for example, output to 5 kgf / cm ² degree than 1 kgf / cm ^2, which is variably controlled by an input signal, the suction side to the oil tank 1 is below the discharge side Connected to the suction side of the constant differential pressure pump 9 and the return passage 10 from the injection nozzle 4. The return passage 10 includes an accumulator 11, a solenoid valve 12, and a check valve 13.

  The control pump 8 has a relief passage 14 for releasing pressure from the discharge side to the suction side, and an orifice 15 serving as an internal pressure relief mechanism in the middle of the relief passage 14.

  A specific structure of such a control pump block 6 is shown in FIG. 2, and this structure will be described below with reference to FIG. 2 while corresponding to the schematic diagram of FIG. The control pump 8 of the control pump block 6 is a so-called electromagnetic pump, and performs a pumping action on the pump body 19 downstream of the suction joint 18 through the cooperation of the suction valve 20 and the discharge valve 21, and the suction valve 20 and the discharge valve 21. Piston 23 is arranged.

  As a driving means for moving the piston 23, the bobbin 26 is provided with an electromagnetic coil 27 in which an electric wire is wound, and an electromagnetic plunger 28 operated by a pulse voltage applied to the electromagnetic coil 27. The electromagnetic plunger 28 is located at the center of the bobbin 26. Is supported by an upper spring 32 and a lower spring 33 in a plunger working chamber 30 formed by a guide pipe 29 inserted into a through hole formed therethrough.

The electromagnetic plunger 28 is connected to the above-described piston 23, and the connected piston 23 is also reciprocated in the cylinder 34 as the electromagnetic plunger 28 reciprocates. The volume in the pump chamber 35 is changed by the reciprocating motion of the piston 23. Fuel pressurized from the discharge valve 21 due to the volume change of the pump chamber 35 is fed into the plunger working chamber 30 through the hole 39, and
One is attached to the pump main body 19 of the control pump 8 and the other is attached to the suction joint 61 of the constant differential pressure pump 9 described below, and the constant differential pressure of the constant differential pressure pump block 7 described below through a hole 38 of the joint rod 37 described below. It is sent to the pump 9.

  A magnetic rod 41 is fitted into the upper end of the guide pipe 29 described above, defines the upper end of the plunger working chamber 30, and supports the upper spring 32. The magnetic rod 41 has a through hole 42 in the center, and the plunger working chamber 30 communicates with the solenoid valve working chamber 43 of the solenoid valve 12.

  The solenoid valve 12 is housed in a solenoid valve case 44 and is biased in a closing direction by a spring 45. The accumulator 11 is connected to the electromagnetic valve working chamber 43 that houses the electromagnetic valve 12, and the check valve 13 is disposed in the connection joint 47 further upward. As described above, the variable control pump 8 constitutes a pump provided in the fuel supply passage 2, the plunger working chamber 30 constitutes a part of the return passage 10, and the built-in electromagnetic valve 12 serves as the return passage. It functions as 10 on-off valves.

  The control pump 8 is provided with an orifice 15 serving as an internal pressure relief mechanism for releasing the remaining internal pressure when the pump is stopped. In order to eliminate the residual pressure, the escape passage 14 is provided and the orifice 15 for restricting the escape amount is provided. However, if a large amount is released, the performance of the pump is also affected. Therefore, it is necessary to appropriately select the orifice diameter. is there.

Returning to FIG. 1, the constant differential pressure pump 9 of the constant differential pressure pump block 7 will be described. The constant differential pressure pump 9 discharges a constant output of, for example, about 8 kgf / cm ² , and pressure adjustment is performed on the discharge side. An accumulator 55 and a solenoid valve 56 are connected via a valve 54 and connected to the fuel injection nozzle 4 described above. A relief passage 58 is provided in parallel with the constant differential pressure pump 9 and the pressure regulating valve 54, and a check valve 59 and an orifice 60 are provided in the relief passage 58. The check valve 59 sets its cracking pressure to a predetermined value, and when the check pressure exceeds the cracking pressure, the check valve 59 is opened to release the pressure on the discharge side to the suction side.

  The fuel injection nozzle 4 is a fuel return type and includes a distributor having a return hole formed in the center of the nozzle holder. The fuel injection nozzle 4 is supplied while swirling from the periphery, and fuel is swirled and sprayed from the injection port. A return passage 10 is connected to the return hole of the fuel injection nozzle 4 and is connected to the discharge side of the control pump 8 via the check valve 13 described above.

  A specific structure of such a constant differential pressure pump block 7 is shown in FIGS. 2 and 3, and this structure will be described below with reference to FIGS. 2 and 3 while corresponding to the schematic diagram of FIG. The constant differential pressure pump 9 of the constant differential pressure pump block 7 is a so-called electromagnetic pump. The pump main body 63 downstream of the suction port 61 has a suction valve 64 and a discharge valve 65, and the suction valve 64 and the discharge valve 65 cooperate with each other. A piston 66 that performs a pumping action is arranged.

  As a driving means for moving the piston 66, the bobbin 67 is provided with an electromagnetic coil 68 in which an electric wire is wound, and an electromagnetic plunger 69 operated by a pulse voltage applied to the electromagnetic coil 68. The electromagnetic plunger 69 is the center of the bobbin 67. Are supported by an upper spring 73 and a lower spring 74 in a plunger working chamber 72 formed by a guide pipe 70 inserted into the formed through hole.

The electromagnetic plunger 69 is connected to the above-described piston 66, and the connected piston 66 is also reciprocated in the cylinder 75 as the electromagnetic plunger 69 reciprocates. By reciprocating the piston 66, the volume in the pump chamber 76 is changed. The fuel pressurized from the discharge valve 65 due to the volume change of the pump chamber 76 is fed into the plunger working chamber 72. The output of the constant differential pressure pump 9 is, for example, 8 kgf / cm ² , but since the output of the control pump 8 varies, for example, from 1 kgf / cm ² to 5 kgf / cm ² , the plunger operation of the constant differential pressure pump 9 is performed. discharge pressure to the chamber 72 is a value obtained by adding the 1~5kgf / cm ² to 8 kgf / cm ^2.

  A magnetic rod 78 is fitted into the upper end of the guide pipe 70 described above, defines the upper end of the plunger working chamber 72, and supports the upper spring 73. The magnetic rod 78 has a through hole 79 in the center, and the plunger operating chamber 72 communicates with the electromagnetic valve movable chamber 81 of the electromagnetic valve 56.

  The solenoid valve 56 is housed in a solenoid valve movable chamber 81 in the discharge joint 80 and is biased in a closing direction by a spring 82. The discharge joint 80 is connected to the fuel injection nozzle 4.

  The pressure regulating valve 54 provided on the discharge side of the constant pressure pump 9 is described in detail in FIG. 3 and is provided in the electromagnetic pump main body 63. A valve seat 85 is provided in the discharge-side space 84 of the discharge valve 65. And is divided into a primary pressure side chamber 84a and a secondary pressure side chamber 84b across the valve seat 85, the primary pressure side chamber 84a is connected downstream of the discharge valve 65, and the secondary pressure side chamber 84b is operated by the plunger. It is connected to the chamber 72.

  A valve body 86 is disposed in the primary pressure side chamber 84a, and this valve body 86 is in contact with a pressure receiving piston 88 described below via a rod 89. The secondary pressure side chamber 84b has a pressure receiving piston 88 and a spring 90 behind the pressure receiving piston 88. The spring 90 presses the pressure receiving piston 88 in the extending direction to open a hole 87 formed in the valve seat 86 in the valve seat 85. When the secondary pressure is applied to the pressure receiving piston 88, it moves against the spring 90 and the valve body 86 is moved in the direction to close the hole 87. That is, the opening area of the hole 87 serving as the fuel supply passage 2 is controlled by the secondary pressure. Thereby, the discharge pressure can be controlled to a predetermined pressure. Note that the pressure is set by changing the position of the adjustment screw 91 on the counter pressure receiving piston side of the spring 90 to the screwing position.

  The constant differential pressure pump 9 is provided with a check valve 59 and an orifice 60 that serve as an internal pressure relief mechanism for releasing the remaining internal pressure when the pump is stopped. A specific example is as follows. That is, the check valve 59 is fixed to the pressure receiving piston 88 and has a valve seat 92 having a through hole 93 at the center, a spring case 94 fixed in the same manner, a spring 95 housed in the spring case 94, and a spring 95. The secondary pressure reaches the valve body 96 through the orifice 60 of the valve seat 92 through the through hole 97.

Opening of the valve body 96, the valve body 96 sandwiching pressure differential is opened and closed (the cracking pressure) as the threshold, for example, is set to 8 kgf / cm ^2, the valve body 96 is opened at 8 kgf / cm ² or more The residual internal pressure is reduced.

In the configuration as described above, the fuel is injected from the fuel injection nozzle 4 by operating the control pump 8 and the constant differential pressure pump 9, and the injection amount from the fuel injection nozzle 4 by changing the output of the control pump 8. Is controlled. That is, the fuel injection nozzle 4, output and the supply pressure applied and the output of the Teisa圧pump 9 of the control pump 8 is sent, the supply pressure of 13 kgf / cm ^2, for example, from 8 kgf / cm ^2.

  When the combustor is stopped (fire extinguished), not only the control pump 8 but also the constant differential pressure pump 9 stops operating. Then, the supply pressure in the plunger working chamber 72 on the discharge side of the constant differential pressure pump 9 remains.

For example, if the supply pressure before the stop is 12 kgf / cm ² , the pressure of about 12 kgf / cm ² remains, but the pressure before and after the check valve 96 is the cracking pressure (set to 8 kgf / cm ² ). Accordingly, the valve body 96 of the check valve 59 is opened, and the residual pressure is released to the suction side of the constant differential pressure pump 9. Thereby, the discharge side of the constant differential pressure pump 9 is maintained at an appropriate pressure. Since the discharge side of the control pump 8 is also released to the suction side by the escape passage 14 and the orifice 15, the pressure on the discharge side of the control pump 8 is discharged to the passage 2.
The cracking pressure of the check valve 59 is set to be equal to or higher than the discharge pressure at the time of maximum combustion of the control pump 8, so that the check valve 59 is closed during combustion and the fuel (oil) is at a constant differential pressure. There is no return to the suction side of the pump 9.

2 Fuel supply passage 3 Fuel flow control device 4 Injection nozzle 6 Control pump block 7 Constant differential pressure pump block 8 Control pump 9 Constant differential pressure pump 10 Return passage
12 Solenoid valve 14 Relief passage 15 Orifice 20 Suction valve 21 Discharge valve 23 Piston 27 Electromagnetic coil 28 Electromagnetic plunger 30 Plunger working chamber 34 Cylinder 41 Magnetic rod 47 Connection joint 54 Pressure adjusting valve 58 Relief passage 59 Check valve 60 Orifice 64 Suction valve 65 Discharge valve 66 Piston 68 Electromagnetic coil 69 Electromagnetic plunger 72 Plunger working chamber 75 Cylinder 78 Magnetic rod 80 Discharge joint 84 Space 85 Valve seat 86 Valve body 87 Hole 88 Pressure receiving piston 89 Rod 90 Spring 91 Adjustment screw 92 Valve seat 93 Through hole 94 Spring case 95 Spring 96 Valve body

Claims (3)

A control pump having a variable output is disposed in a fuel supply passage for sucking fuel from a fuel tank and supplying the fuel injection nozzle, and a constant differential pressure pump for outputting a constant output to the output of the control pump. In a constant differential pressure type fuel flow control device in which a return flow path connected to a return hole of an injection nozzle is connected to a fuel supply flow path between the control pump and the constant differential pressure pump, the discharge side of the constant differential pressure pump Is provided with a relief passage in parallel to the pressure regulation valve and the constant differential pressure pump. The relief passage includes a check valve and an orifice connected in series to the check valve. The constant differential pressure type fuel flow control device, wherein the check valve is provided in a pressure receiving piston constituting the pressure regulating valve. The check valve is fixed to a pressure receiving piston constituting the pressure regulating valve and has a through hole in the center, a valve body seated on the valve seat, and a valve seat that presses the valve body. constant difference pressure fuel flow control device according to claim 1, characterized by comprising more the spring in the spring case. The orifice is constant difference pressure fuel flow control device according to claim 1, characterized in that provided in the through hole forming a fixed valve seat in the pressure piston.

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